; diehard ed Fok Tatea dik . Sie card woe or wee ED eta RP asa Pt te ame 1 oe -35- ation from RhtC® in the snail liver sample. Although the 7 curves for peaks for both Co?’ and ¢0°° are present in the 7 both samples, the peak for co is not present. This is expected. The C028 4n the samples would have passed through about 12 half lives and would be present in insignificant amounts. mm", on the other hand, with a half life of 310 days would have gone through only about three half lives and its .84 MEV 7 peak 1s evident in the curves from both samples. The .84 MEV peak of Mn>4 4s easily confused with the MEV peak of co, the 37 .81 In those samples containingboth isotopes, peak from Min 24 can be detected only after the C028 has been allowed to decay out as shown in Fig.10, or after chemical separation. Figure 11 shows f spectrum curves from three clam kidney samples made 4, 18, and 31 months after the dates of collection. | The Co”! and 0° peaks are present in all three curves. In the curve analyzed 4 months after the date of collection the .81 MEV C08 peak is very strong. In the other two curves this peak has decayed out and is replaced by the .84 MEV vin>4 peak. Representative whole samples in which the 1.12 MEV 7 peak of zn°> has been observed include the following: Organism Date of collection Site of collection Whole fish Nov. 8, 1952 Janet Is., Eniwetok Fish skin May, June, 1954 Belle Is., Eniwetok Fish muscle " " n " " " Fish bone 1 1 " n it iH Fish liver n ft tt i N 1